Liquid crystal displays (LCDs) have been widely applied in electrical products. Currently, most of LCDs are backlight type LCDs, and comprise a liquid crystal panel and a backlight module. According to the position of the light sources, the backlight module can be classified into a side-light type or a direct-light type, in order to provide LCDs with backlight sources.
Light emitting diodes (LEDs) have several beneficial characteristics, including low electrical power consumption, low heat generation, long operational life, small volume, good impact resistance, fast response and excellent stability for emitting color light with stable wavelengths. These characteristics have made the LEDs suitable for light sources of the backlight module.
However, the LEDs with different colors have different luminous efficiency. For example, the luminous efficiency of a normal green LED is lower than the luminous efficiency of a red or blue LED. Therefore, when mixing the light of the LEDs with different colors to form a white light, a color shifting defect is susceptible to occur.
For improving the above-mentioned detect, an improving method is to add the number of LEDs with lower luminous efficiency, such as to add the number of green LEDs. However, this method is susceptible to increase the cost and heat of the LEDs.
Another improving method is to charge the arrangement of the LEDs. For example, the green LED is disposed close to a light output surface of a light guide plate (i.e. the upper surface of the light guide plate). However, this method still can not sufficiently improve the color shifting defect.
As a result, it is necessary to provide a backlight module and a display apparatus to solve the problems existing in the conventional technologies, as described above.